# US 11,309,389 B2 · Epitaxial wafer and switch element and light-emitting element using same

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- Number: US 11,309,389 B2
- Document ID: US11309389B2
- Status: Granted
- Kind: B2
- Application number: 14/648,609
- Filed: 2013-11-21
- Published: 2015-10-15
- Granted: 2022-04-19
- Earliest claimed: 2012-11-30
- Assignees: Lx Semicon Co., Ltd.
- Applicants: LX Semicon Co., Ltd.
- Inventors: Seok Min Kang; Ji Hye Kim; Heung Teak Bae
- Web page: https://patentgrep.com/patent/US11309389B2

## CPC

- H10D 62/8325: {Silicon carbide}
- H10D 8/60: Schottky-barrier diodes
- H10D 30/66: Vertical DMOS [VDMOS] FETs
- H10D 62/106: {having supplementary regions doped oppositely to or in rectifying contact with regions of the semiconductor bodies, e.g. guard rings with PN or Schottky junctions}
- H10D 62/156: {Drain regions of DMOS transistors}
- H10H 20/8215: {characterised by crystalline imperfections, e.g. dislocations; characterised by the distribution of dopants, e.g. delta-doping}
- H10H 20/826: comprising only Group IV materials
- H10P 14/2904: {Silicon carbide}
- H10P 14/3402: {characterised by the chemical composition}
- H10P 14/3408: {Silicon carbide}
- H10D 62/53: the imperfections being within the semiconductor body
- H10H 20/01335: {the light-emitting regions comprising nitride materials}
- H10H 20/825: containing nitrogen, e.g. GaN
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

An epitaxial wafer includes an epitaxial layer disposed on a substrate. The epitaxial layer includes a first semiconductor layer disposed on the substrate and a second semiconductor layer disposed on the first semiconductor layer and having a thickness that is thicker than that of the first semiconductor layer. A surface defect density of the second semiconductor layer is 0.1/cm2 or less.

## Claims

### Claim 1

An epitaxial wafer comprising:
a substrate; and
an epitaxial layer on the substrate, wherein the epitaxial layer includes silicon carbide,
wherein the epitaxial layer comprises:
a first semiconductor layer on the substrate, and
a second semiconductor layer disposed on the first semiconductor and having a thickness thicker than a thickness of the first semiconductor layer,
wherein a density of a Basal Plane Dislocation (BPD) of the first semiconductor layer is 30/cm2 or less,
wherein a density of a Etch Pit Density (EPD) of the first semiconductor layer is 3,000/cm2 or less, and
wherein a ratio of BPD/EPD of the first semiconductor layer is 0.01 or less.

### Claim 2 (depends on 1)

The epitaxial wafer of claim 1, wherein any one of the first semiconductor layer and the second semiconductor layer comprises a silicon carbide nitride semiconductor layer.

### Claim 3 (depends on 1)

The epitaxial wafer of claim 1, wherein any one of the first semiconductor layer and the second semiconductor layer comprises an aluminum silicon carbide semiconductor layer.

### Claim 4 (depends on 1)

The epitaxial wafer of claim 1, wherein a doping concentration of the first semiconductor layer is higher than a doping concentration of the second semiconductor layer.

### Claim 5 (depends on 1)

The epitaxial wafer of claim 1, wherein the substrate comprises silicon carbide.

### Claim 6 (depends on 1)

The epitaxial wafer of claim 1, wherein the epitaxial layer comprises at least one of 3C-SiC, 4H-SiC and 6H-SiC.

### Claim 7 (depends on 1)

The epitaxial wafer of claim 1, wherein the first semiconductor layer is a buffer layer, and the second semiconductor layer is an active layer.

### Claim 8 (depends on 1)

The epitaxial wafer of claim 1, wherein a thickness of the first semiconductor layer is 0.5 μm to 1 μm.

### Claim 9

A switch element comprising:
a substrate;
a first semiconductor layer on the substrate;
a second semiconductor layer on the first semiconductor layer;
an anode electrode on the second semiconductor layer; and
a cathode electrode under the substrate,
wherein the first semiconductor layer and the second semiconductor layer include silicon carbide,
wherein at least one of the first semiconductor layer and the second semiconductor layer comprises one of 3C-SiC, 4H-SiC and 6H-SiC,
wherein the second semiconductor layer has a thickness thicker than a thickness of the first semiconductor layer,
wherein a density of a Basal Plane Dislocation (BPD) of the first semiconductor layer is 30/cm2 or less,
wherein a density of a Etch Pit Density (EPD) of the first semiconductor layer is 3,000/cm2 or less, and
wherein a ratio of BPD/EPD of the first semiconductor layer is 0.01 or less.

### Claim 10

A light emitting element comprising:
a substrate;
an epitaxial layer on the substrate; and
a light emitting structure disposed on the epitaxial layer and including at least a first conductive semiconductor layer, an active layer and a second conductive semiconductor layer,
wherein the epitaxial layer comprises:
a first semiconductor layer on the substrate; and
a second semiconductor layer on the first semiconductor layer,
wherein the first semiconductor layer and the second semiconductor layer include silicon carbide,
wherein at least one of the first semiconductor layer and the second semiconductor layer comprises one of 3C-SiC, 4H-SiC and 6H-SiC,
wherein the second semiconductor layer has a thickness thicker than a thickness of the first semiconductor layer,
wherein a density of a Basal Plane Dislocation (BPD) of the first semiconductor layer is 30/cm2 or less,
wherein a density of a Etch Pit Density (EPD) of the first semiconductor layer is 3,000/cm2 or less, and
wherein a ratio of BPD/EPD of the first semiconductor layer is 0.01 or less.